Just a short question
After electrolysis for 15 minutes, 140 cm3 of gas was collected
in the test tube at electrode A. 120 cm3 of chlorine gas was
collected at D instead of 140cm3 that was expected. Explain.
The info given by the question is incomplete, thus no
answer can be definite.
Notwithstanding, nevertheless, regardless, it is common enough
that volumes of gases collected over electrodes do not fit
theoretical volumes. Reasons include :
- Gases undergoing hydrolysis, eg. chlorine + water
--> chloric(I) acid (latin name : hypochlorous
acid) + hydrochloric acid
- Graphite anodes reacting with the oxygen produced at the
anode, to form carbon monoxide gas (carbon dioxide gas would not be
an acceptable answer, based on stoichiometry).
- etc.